Base station antennas that operate in multiple frequency bands and that provide omnidirectional coverage are known in the art. These base stations typically operate in one or more portions of the 700 MHz to 5.9 GHz frequency range. Arrays of radio frequency (“RF”) radiators that are included in these base station antennas may be mounted on multiple backplanes. In order to support operation in multiple frequency bands, a large number of RF ports and associated feed networks, arrays of radiators, and the like need to be provided. This may result in space constraints within the interior of the base station antenna.
In many cases, some parameters of the antenna need to be adjusted. For example, there may be a need to electronically adjust the elevation or “tilt” angle of the antenna beams generated by the radiators operating in one or more frequency bands. This is accomplished by adjusting the phase of the sub-components of an RF signal that are radiated through each of the radiating elements. In cases where the antenna provides omnidirectional coverage, it will typically be necessary to adjust the phase with respect to radiators that are mounted on multiple backplanes. Typically, all of these radiators are adjusted synchronously to ensure that consistent phase adjustment is achieved.
Mechanisms are known in the art that may accomplish synchronous adjustment of the phase for radiators that are mounted on multiple backplanes. However, in order to adapt to the complex space environment inside the antenna, these mechanisms are typically composed of multiple components, resulting in a large apparatus and difficult and time-consuming assembly, and the apparatus may also complicate the design and assembly of other internal components of the antenna.